I think It’s more an idea than it is an action … same as marriage .. those state signed certificates don’t mean a thing.
Discussion
What would constitute adultery in your estimation? What would constitute a marriage?
A marriage is the idea of how two people treat each other in relationship, adultery is more like a subset of lieing that would be the result of having intimacy with someone that your
Marriage had agreed not to, and it’s smart for a marriage to agree on this if it wants the blessings of many things… adultery makes a liar of someone but also introduces health risks (consequences), the longer the lie goes on the worse the damage to a marriage can be done.